At one level, answering why the Green Party of England and Wales supports a "yes" vote in the Scotland independence referendum is easy.
You might have noticed the name; our members in Scotland chose independence in 1990, and since then we've agreed that on issues specifically relating to Scotland, the England and Wales party will take its lead from the Scottish Green Party.
And the Scottish Green Party is throwing itself heart and soul into the Green Yes campaign, part of the broader "radical yes" campaign that we mightn't have heard much about south of the border, where the limited focus has all been on the SNP and Alex Salmond's "really, it's no big change at all" approach, rather than on the campaigners who see this as a chance to build an exciting, new, different, fair and equitable society.
But our support for a "yes" vote isn't just a matter of passively following the lead of the Scottish Green Party, nor is it even just our no-comprise respect for the principle of self-determination, the right of peoples to decide their own future.
First, we see the exciting possibilities of a new state in Scotland. It's a country whose voters have never been neoliberal, never voted neoliberal, where active espousal of the privatisation, austerity agenda that's done so much to protect and enhance the position of the rich in our society has got the Tories to where they are today north of the border, which is nowhere at all.
There's clearly a great possibility of rebuilding the welfare safety net that this government has so rent asunder, or stopping and reversing the privatisation of the NHS, of taking advantage of the tremendously rich renewable energy resources that our current government is determined to ignore as it rushes to appease the Ukip anti-wind lobby and the oil and gas companies that help to fund the Tories (and for whom so many of their MPs work).
It could be a great model for England and Wales to follow.
It's a pity that so much of the debate has been around not such exciting possibilities, but political posturing on the currency and membership of the EU, when it is obvious these are issues that need to be negotiated after a "yes" vote, rather than caught up in less than honest statements in the campaign before the vote.
And there's a second reason for the Green Party of England and Wales to enthusiastically back a "yes" vote: we see exciting possibilities for what will be left of the United Kingdom. I was a few months ago at a public meeting and a unionist in the audience pointed out, correctly, that there's been very little discussion of the constitutional implications for "the rest" if the Scots do vote "yes". "Won't there be constitutional chaos?" he asked.
My response was: "Yes, isn't that great!" We badly need some creative chaos, to reshape, to focus on our failing political structures - constitutional structures that haven't basically changed since women got the vote. We've got nearly a century's worth of stalled reforms to deliver.
There will be strong pressure to produce a written constitution, and many of the oddities, the corruptions, the sheer anachronism of our current arrangements would surely not survive the cold light of exposure, from our banana republic-style House of Lords to the dangerous privileges of the City of London Remembrancer.
Real change in our method of government - introducing more, much more, democracy, guaranteeing the transparency of what's all too often done in secret, seeing how Scotland, already with a proportional representation election system, can create real change when set free to make real choices - would provide if not everything we need to restore our democracy, certainly some big steps in the right direction.
And to those who fear the maths that in previous elections, without Scotland, the figures show many more Conservative victories, draw comfort: change is coming in politics, real change. The future isn't going to be like the past, whatever shape takes. It makes no sense to think that everything else would change, and voting patterns stay the same ... indeed they are already very clearly changing.
Natalie Bennett is tonight addressing a Green Yes campaign meeting in Edinburgh with Green MSP Alison Johnstone.